Vehicle-mounted communication device and road-to-vehicle communication device

ABSTRACT

A vehicle-mounted communication device and a road-to-vehicle communication device are provided which each allow communication of information using a simple structure by making leakage of information difficult. Information including encryption information is communicated between an on-road apparatus  10  having a memory  28  in which an electronic key A is stored, and a vehicle-mounted apparatus  30  having a storage circuit  48 . Encrypted route information and the like are stored as is in the vehicle-mounted apparatus  30 . Encryption and decoding are executed at an on-road apparatus side. In reception of charges, encrypted information from an IC card  62  having a memory  70  in which a security mechanism is stored passes through the vehicle-mounted apparatus and is transferred to the on-road apparatus. The encrypted information from the IC card  62  is decoded with the on-road apparatus. Accordingly, the encrypted information is mutually transferred between these apparatuses and the vehicle-mounted apparatus does not require encryption or decoding. As a result, the security of a system can be improved.

This application is a continuation, of Application No. PCT/JP98/00342,filed in Japan on Jan. 28, 1998, and which designated the U.S.A.

TECHNICAL FIELD

The present invention relates to a vehicle-mounted communication deviceand a road-to-vehicle communication device, and particularly to avehicle-mounted communication device mounted on a vehicle and to aroad-to-vehicle communication device which effects communicationprocessing between the vehicle-mounted communication device and anon-road apparatus installed on a road side.

BACKGROUND ART

In recent years, an automatic toll collecting system has been developedwhich utilizes a toll pre-paid type card or a toll post-payment typecard to receive charges for using charged facilities, for example, toreceive a toll charged on a toll road. In the automatic toll collectingsystem, on-road apparatuses for road-to-vehicle communications(hereinafter referred to as “on-road apparatuses”) with antennas, eachof which serves as an interrogator for making inquiries with respect toa vehicle for information in order to collect tolls automatically atentrance and exit gates of the toll road, are provided on the road side,and each of vehicle-mounted apparatuses for road-to-vehiclecommunications communications (hereinafter referred to as“vehicle-mounted apparatuses”) with antennas, each of which serves as aresponder for responding to the information, with respect to which aninquiry was made is mounted on the vehicle, whereby the information istransferred by radio communications between the vehicle-mountedapparatus and the on-road apparatus.

In order to transfer the information between the vehicle-mountedapparatus and the on-road apparatus, toll information or vehicleinformation about a vehicle, and information about a user must bestored. For this reason, an IC card in which a large quantity of datacan be stored may be used with information being written therein.

However, as described above, when the information is transferred betweenthe vehicle-mounted apparatus and the on-road apparatus or when theinformation is transferred to and received from the IC card, theinformation is used with a form thereof left unchanged. As a result,there exists a problem that a person not intended by a user can easilydisclose contents of the information.

Accordingly, there has been proposed an electronic identification systemin which secrecy is kept by identifying that a transmitted secret codesuch as an inherent code coincides with at least one of a plurality ofpredetermined secret codes, thereby resulting in improvement of security(see Japanese Patent Application Laid-Open (JP-A) No. 6-511097).

However, in a conventional electronic identification system, only onekind of secret code is assigned to a user, and therefore, secret codesmust be set correspondingly to the number of users so as to identify agreat number of users. For this reason, in a road-to-vehiclecommunication device in which information is transferred to and receivedfrom each of a great number of users, the load on the device increases.Further, only one kind of secret code is assigned to a user, andtherefore, when the secret code leaks out, the security of a system usedby the user, namely, of the road-to-vehicle communication device,deteriorates.

Further, in order to collect a toll automatically by transferringinformation between the vehicle-mounted apparatus and the on-roadapparatus, vehicle information about a vehicle and user informationabout a user, such as a balance of charges for accounting must bestored. Accordingly, the IC card in which a large quantity of data canbe stored may be used with information being written therein.

However, in a case of transferring the above-described information, whenthe information is used in a general description form, there exists aproblem that a person that is not intended by a user or an informationprovider can illegally alter or falsify the contents of the informationand can also unlawfully utilize such information.

Accordingly, there has been proposed an automatic toll collecting systemin which information communicated between an on-road apparatus and avehicle-mounted apparatus is encoded so as to improve the security (seeJapanese Patent Application Laid-Open (JP-A) No. 6-60237). In thissystem, encoded information stored in an IC card or encoded informationfrom the on-road apparatus is made into a common sentence structure(made into a general descriptive form) in the vehicle-mounted apparatus,and processing for user information such as a balance of charges iseffected.

However, in the conventional automatic toll collecting system, the userinformation made into a common sentence structure in the vehicle-mountedapparatus is temporarily stored. Accordingly, a person that is notintended by the user or the information provider can easily falsify thecontents of the user information about a user such as the balance ofcharges, and the like, thereby resulting in deterioration of security.

SUMMARY OF THE INVENTION

In view of the above-described circumstances, an object of the presentinvention is to provide a vehicle-mounted communication device and aroad-to-vehicle communication device, that can improve security using asimple structure and in a simple manner.

In addition to the above-described object, an object of the presentinvention is to provide a vehicle-mounted communication device and aroad-to-vehicle communication device that can allow communication ofinformation using a simple structure by making it difficult to leak orfalsify information.

In order to achieve the above-described objects, a vehicle-mountedcommunication device comprises: transmitting/receiving means providedfor communication of information with road-side communication meanslocated at a road side; and relay means for relaying encryptioninformation received from the road side by the transmitting/receivingmeans to an IC card which includes storage means for storing userinformation regarding a balance of charges and which also includesencryption means encrypts and outputs output information based on theuser information and decodes encrypted input information regarding theuser information.

The invention is a vehicle-mounted communication device as describedabove, wherein the relay means relays the output information encryptedby the IC card to the transmitting/receiving means.

The invention is a vehicle-mounted communication device as describedabove, further comprising encryption information storage means in whichthe encryption information is temporarily stored, wherein thetransmitting/receiving means stores the encryption information in theencryption information storage means and transmits as is the encryptioninformation stored in the encryption information storage means.

The invention is a vehicle-mounted communication device as describedabove, wherein at least one of the IC card and the road-sidecommunication means outputs a portion of the output information in astate without encryption and information display means for displayingthe portion of the output information outputted without being encryptedis further provided.

The invention is a road-to-vehicle communication device comprising: avehicle-mounted communication device as described above, and road-sidecontrol means being located at a road side, including road-sidecommunication means and provided for intercommunication of informationwith the vehicle-mounted communication device, and also includingroad-side encryption means for encrypting transmitted information anddecoding received information.

The invention is a road-to-vehicle communication device as describedabove, wherein road-side encryption means of the road-side control meansinstalled at an entrance gate effects encryption of transmittedinformation and road-side encryption means of the road-side controlmeans installed at a toll reception gate effects only decoding ofreceived information.

The invention is a road-to-vehicle communication device as descibedabove, wherein the transmitted information is accounting informationregarding accounting processing of charged facilities.

The invention is a road-to-vehicle communication device comprising:road-side control means being located at a road side, includingroad-side communication means and provided for intercommunication ofinformation with vehicle-mounted communication means, and also includingfirst encryption means for encrypting transmitted information, anddecoding received information with a first electronic key; informationcontrol means including information transfer means which stores thereinuser information regarding at least one of a vehicle and a user andthrough which information is mutually transferred with respect to thevehicle-mounted communication means, and also including secondencryption means for encrypting output information, and decoding inputinformation with a second electronic key; and vehicle-mounted controlmeans being installed on a vehicle side, including vehicle-mountedcommunication means provided for intercommunication of information withrespect to the road-side communication device and for mutual transfer ofinformation with respect to the information control means, and alsoincluding third encryption means which, during the communication ofinformation, encrypts transmitted information and decodes receivedinformation with the first electronic key, and which during the transferof information, encrypts output information and decodes inputinformation with the second electronic key.

The invention of claim 9 is a road-to-vehicle communication deviceaccording to claim 8, wherein each group of the first encryption meansand the road-side communication means, the second encryption means andthe information transfer means, and the third encryption means and thevehicle-mounted communication means are provided on the same substrate.

At the vehicle-mounted communication device intercommunication ofinformation is carried out with respect to the road-side communicationmeans located at the road side, with the transmitting/receiving means.The IC card is attachable and detachable at the vehicle-mountedcommunication device and stores in the storage means the userinformation regarding the balance of charges. The encryption meansencrypts output information based on the user information and thenoutputs. The encryption means also decodes the encrypted inputinformation regarding the user information. Among the informationreceived from the road side by the transmitting/receiving means, theencryption information is relayed to the IC card by the relay means.Accordingly, the encryption information passes through thevehicle-mounted communication device in a form of being left unchanged,and thus, the secrecy of the encryption information is maintained andthe security thereof is protected.

As described above, the above-described relay means relays the outputinformation encrypted by the IC card to the transmitting/receivingmeans, so as to transmit the output information based on the encrypteduser information from the IC card to the road side in a form of beingleft unchanged. As a result, the secrecy of the output information canbe maintained and the security thereof can be protected.

As described above, the vehicle-mounted communication device can furtherinclude the encryption information storage means in which encryptioninformation is temporarily stored. The encryption information storagemeans stores therein encryption information with thetransmitting/receiving means. Further, the stored encryption informationis transmitted as is by the transmitting/receiving means. As a result,the encryption information from the road side, which is unrelated to theuser information stored in the IC card and is desired to be retained,for example, gate information which indicates an entrance gate, amid-route, and the like, can be held in a form of being left unchangedand can also be transmitted to the road side. Accordingly, the secrecyof the information from the road side can be maintained and the securitythereof can be protected.

Further, as described above, the information display means is furtherprovided which outputs the portion of output information desired to bemade known to a user without encryption by the IC card and displays theportion of the output information outputted without being encrypted,thereby resulting in that the user can confirm completion ofcommunication or details that are results of accounting processing.

As described above, in the road-to-vehicle communication device of thepresent invention, the IC card is mounted in the vehicle-mountedcommunication device and information is mutually communicated withrespect to the road-side control means located at the road side. Theroad-side encryption means of the road-side control means encryptstransmitted information and decodes received information. Accordingly,transmitted information to be transmitted from the road side passesthrough the vehicle-mounted communication device in a form of beingencrypted. As described above as well, processing such as reception ofcharges can be effected for the IC card in such a manner that accountinginformation regarding accounting processing of charged facilities istransmitted and received as the transmitted information, and theresulting information also passes through the vehicle-mountedcommunication device in the form of being encrypted, thereby resultingin no damage to the secrecy of the information.

As described above, the road-to-vehicle communication device encryptstransmitted information with the road-side encryption means of theroad-side control means located at an entrance gate and decodes receivedinformation by the road-side encryption means of the road-side controlmeans located at a toll reception gate. As a result, the vehicle-mountedcommunication device does not have encryption means, and therefore,irregularities in charge payment caused by analysis of a cipher of thevehicle-mounted communication device can be made impossible.

Further, according to the invention, information is mutuallycommunicated between the road-side communication means of the road-sidecontrol means and the vehicle-mounted communication means of thevehicle-mounted control means. Further, information is mutuallytransferred between the vehicle-mounted communication means of thevehicle-mounted control means and the information transfer means of theinformation control means.

During the communication of information, the road-side control meansuses the first encryption means, with the first electronic key, toencrypt transmitted information to be transmitted to the vehicle-mountedcontrol means and to decode received information from thevehicle-mounted control means. Further, the vehicle-mounted controlmeans uses the third encryption means, with the first electronic key, toencrypt transmitted information to be transmitted to the road-sidecontrol means and to decode received information from the road-sidecontrol means. Accordingly, information can be encrypted using the firstelectronic key so as to be mutually communicated between the road-sidecontrol means and the vehicle-mounted control means, and therefore, thesecrecy of information is maintained and the security thereof is therebyprotected.

During the transfer of information, the vehicle-mounted control meansuses the third encryption means, with the second electronic key, toencrypt output information and to decode input information. Theinformation transfer means stores therein user information regarding atleast one of a vehicle and a user. When the user information isoutputted to the vehicle-mounted control means, the information transfermeans uses the second encryption means, with the second electronic key,to encrypt, as output information, the user information and to decodeinput information from the vehicle-mounted control means. Accordingly,information can be encrypted using the second electronic key so as to bemutually transferred between the vehicle-mounted control means and theinformation transfer means, and therefore, the secrecy is maintained andthe security is thereby protected.

As described above, secrecy is independently maintained using differentelectronic keys respectively for the communication of information andfor the transfer of information, and therefore, the security of theroad-to-vehicle communication device can be improved. Further, sincesecrecy is independently held, leakage of information can be restrainedto the minimum until the secrecy becomes clear.

The above-described first, second, and third encryption means are eachthat which maintains secrecy, and therefore, so long as these encryptionmeans are each made clear, the secrecy can be made clear. Accordingly,as described above as well, by providing each of the first encryptionmeans and the road-side communication means, the second encryption meansand the information transfer means, and the third encryption means andthe vehicle-mounted communication means on the same substrate, on thesame chip, for example, decoding such as analysis becomes difficult andthe security of the road-to-vehicle communication device can beimproved.

In the vehicle-mounted communication device of the present invention,among the information received from the road side by thetransmitting/receiving means, the encryption information is relayed bythe relay means to the IC card, and therefore, the encryptioninformation passes through the vehicle-mounted communication device inthe form of being left unchanged. Accordingly, there is an effectwherein the secrecy of the encryption information is maintained and thesecurity can be protected.

In the road-to-vehicle communication device of the present invention,the IC card is mounted in the vehicle-mounted communication device whichrelays the encryption information and information is mutuallycommunicated with respect to the road-side control means which encryptstransmitted information and decodes received information. Accordingly,there is an effect wherein the security can be maintained without thesecrecy of the information being damaged.

Further, secrecy is independently maintained using different electronickeys, and therefore, there is an effect wherein the security of theroad-to-vehicle communication device can be improved.

Further, by providing the first, second, and third encryption means,respectively together with corresponding road-side communication means,information transfer means, and vehicle-mounted communication means, onthe same substrate, there is an effect wherein decoding such as analysisbecomes difficult, improving the security of the road-to-vehiclecommunication device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram that shows an automatic toll receiving systemaccording to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view that shows a mid-route in theautomatic toll receiving system of the first embodiment.

FIG. 3 is a block diagram that shows a vehicle-mounted apparatus of thefirst embodiment.

FIG. 4 is a block diagram that shows one example of an on-road apparatusof the first embodiment.

FIG. 5 is a block diagram that shows a structure of an IC card of thefirst embodiment.

FIG. 6 is a flow chart that shows a flow in a process of thevehicle-mounted apparatus of the first embodiment.

FIG. 7 is a flow chart that shows a flow in a process of the on-roadapparatus of the first embodiment in a mid-route.

FIG. 8 is a flow chart that shows a flow in an exit gate process of thevehicle-mounted apparatus of the first embodiment.

FIG. 9 is a flow chart that shows a flow in a process of the on-roadapparatus at an exit gate of the first embodiment.

FIG. 10 is a flow chart that shows a flow in a process of the IC card ofthe first embodiment.

FIG. 11 is an image diagram that shows the relationship between theon-road apparatus, the vehicle-mounted apparatus, and the IC card of thefirst embodiment when information is mutually transferred therebetween.

FIG. 12 is a block diagram that shows an automatic toll receiving systemaccording to a second embodiment of the present invention.

FIG. 13 is a block diagram that shows a vehicle-mounted apparatus of thesecond embodiment.

FIG. 14 is a block diagram that shows one example of an on-roadapparatus of the second embodiment.

FIG. 15 is a block diagram that shows an IC card and an informationwriting device of the second embodiment.

FIG. 16 is a flow chart that shows a process routine of the informationwriting device of the second embodiment.

FIG. 17 is a flow chart that shows a process routine of thevehicle-mounted apparatus with respect to the information writing deviceof the second embodiment.

FIG. 18 is a flow chart that shows a communication processing routine ofthe vehicle-mounted apparatus of the second embodiment.

FIG. 19 is a flow chart that shows a process routine of the on-roadapparatus of the second embodiment.

FIG. 20 is a flow chart that shows a process routine of the IC card ofthe second embodiment.

FIG. 21 is an image diagram showing transmitting and receiving ofinformation, which is effected between the information writing deviceand the vehicle-mounted apparatus of the second embodiment.

FIG. 22 is an image diagram showing transmitting and receiving ofinformation, which is effected between an IC card read/write device andthe vehicle-mounted apparatus of the second embodiment.

FIG. 23 is an image diagram showing transmitting and receiving ofinformation, which is effected between the on-road apparatus and thevehicle-mounted apparatus and between the IC card read/write device andthe vehicle-mounted apparatus in the second embodiment.

BEST MODES FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will hereinafter be described indetail with reference to the accompanying drawings. The presentembodiments each show that the present invention is applied to anautomatic toll receiving system for automatically receiving a toll fromeach of vehicles running on a toll road or the like.

In the automatic toll receiving system, information is transferredbetween an apparatus mounted on a vehicle and an on-road apparatushaving flat antennas (or other antennas, for example, Yagi antennas)provided at ground portions of an entrance gate, an exit gate, and thelike through radio communications to thereby determine a traffic section(route) over which the vehicle has been driven and the type of thevehicle and automatically accept a traffic toll or the like withoutstopping the vehicle at the entrance and exit gates.

First Embodiment

A first embodiment will first be described.

As shown in FIG. 1, an automatic toll receiving system of the presentembodiment is structured to include an on-road apparatus 10 provided onthe road side and a vehicle-mounted apparatus 30 mounted on a vehicle,and information is mutually transferred between the on-road apparatus 10and the vehicle-mounted apparatus 30 by radio communications. Theon-road apparatus communicating with the vehicle-mounted apparatus 30 isprovided with flat antennas (or other antennas, for example, Yagiantennas) for transmitting and receiving various information and isdisposed at each of an entrance gate of a toll road, a mid-route (checkbarrier), and an exit gate or the like. The on-road apparatus 10includes a memory 28 (see FIG. 4) in which an electronic key A forencryption of information is stored and the vehicle-mounted apparatus 30includes a storage circuit 48 (see FIG. 3) in which the above-describedencryption information is stored, as will be described in detail later.When information is mutually transferred between the on-road apparatus10 and the vehicle-mounted apparatus 30 by radio communications,transmitted information is encrypted using the electronic key A on theside of the on-road apparatus and is transmitted to the vehicle-mountedapparatus 30. This encryption (or decoding) can be provided using amethod based on Data Encryption Standard (a so-called DES) or the like.

An IC card 62 (which will be described in detail later) in which variousinformation is stored is provided so as to be detachable from thevehicle-mounted apparatus 30. Information is mutually transferredbetween the vehicle-mounted apparatus 30 and the IC card 62. The IC card62 includes a memory 70 (see FIG. 5) in which a security mechanism Mprovided with a process for encrypting or decoding information isstored. This security mechanism is used to manufacture or issue the ICcard 62 and is in advance set in accordance with an operation thereof. Aplurality of logic which are provided for encryption or decoding by thesecurity mechanism can be stored on the side of the on-road apparatusand any one security mechanism can be selectively used.

Next, the vehicle-mounted apparatus 30 and the on-road apparatus 10communicating with the vehicle-mounted apparatus 30 will be described indetail. Further, in the present embodiment, a description will be givenin which an on-road apparatus provided in the mid-route 200 is shown asan example. Further, for simplifying an explanation, a mid-route antenna218 provided for radio communication with a vehicle 90 traveling along alane 202 and a mid-route antenna control device 232 are used for theexplanation. Further, a vehicle-mounted battery (not shown) is connectedto the vehicle-mounted apparatus 30.

As shown in FIG. 2, in the mid-route 200 located immediately before orafter a branching point of a toll road, two lanes, the lane 202 and alane 204, are provided side by side between a ground 208 and a ground214. An arch 216 is disposed between the ground 208 and the ground 214in such a manner as to extend over the lanes 202 and 204. Routerecognizing antennas 218, 220, and 222 are disposed on the arch 216. Theroute recognizing antenna 218 is located above the lane 202 for radiocommunication with a vehicle traveling along the lane 202. The routerecognizing antenna 222 is located above the lane 204 for radiocommunication with a vehicle traveling along the lane 204. The routerecognizing antenna 220 is disposed substantially at an intermediatepoint between the route recognizing antennas 218 and 222 such that it islocated above a centerline 206 between the lanes 202 and 204, for radiocommunication with a vehicle running so as to straddle the boundarybetween the lanes 202 and 204.

A route control center 230 equipped with the route recognizing antennacontrol device 232 is disposed on the ground 214. The route recognizingantennas 218, 220, and 222 are connected to the route recognizingantenna control device 232.

In the above-described mid-route 200, the route recognizing antennacontrol device 232 transmits route information, which represents thekind of route a vehicle 90 traveled on a toll road, to thevehicle-mounted device 30 mounted on the vehicle 90, via the routerecognizing antenna. The route recognizing antenna control device 232can be connected to a central computer for collectively controlling arunning state of the vehicle on the toll road. A recovery gate can bedisposed at the mid-route 200 so as to write the route informationindicating a mid-route into the vehicle-mounted apparatus using the ICcard 62. The recovery gate is provided with an IC card read/write devicein which the IC card 62 is removably mounted. The IC card read/writedevice is connected to the central computer. The recovery gate may bedisposed at a parking area or a service area.

Meanwhile, at the entrance gate that is another on-road apparatus,entrance information of the toll road is transmitted to thevehicle-mounted apparatus 30 mounted on the vehicle. Further, at theexit gate, exit information which indicates an exit gate is transmittedto the vehicle-mounted apparatus 30 mounted on a vehicle, and forexample, traffic charges or tolls corresponding to the section (route)run by the vehicle or to the type of vehicle are automatically received.

This entrance information and exit information can be transferred by anoperator via an IC card. For example, when a communication error occurs,at the recovery gate for writing in data such as the entranceinformation which indicates an entrance gate using the IC card or forreading out data stored in the vehicle-mounted apparatus, the IC cardread/write device to which the IC card 62 can be attached and detachedis used to enable execution of transfer of the entrance and exitinformation. Codes such as numbers or the like, which are in advanceassigned respectively to positions of toll roads, may be used for theentrance information and route information.

As shown in FIG. 3, the vehicle-mounted apparatus 30 is provided with areceiving antenna 32 for receiving a data signal transmitted from theon-road apparatus. The receiving antenna 32 is connected via a datasignal receiving circuit 44 to a signal processing circuit 46 structuredso as to include a microcomputer. The microcomputer of the signalprocessing circuit 46 stores therein a processing program, which will bedescribed below.

A storage circuit 48 is connected to the signal processing circuit 46.Information regarding the vehicle-mounted apparatus is stored in thestorage circuit 48. Namely, when the vehicle-mounted apparatus ismounted on a vehicle, a vehicle number (the number recorded on a numberplate) serving as an ID code and information regarding the type of avehicle on which the vehicle-mounted apparatus is mounted are in advancestored in the storage circuit 48. Further, a region in which encryptioninformation is stored is in advance allocated in the storage circuit 48.The encryption information includes the entrance information (entrancenumber, date and time at which the vehicle passed through the entrancegate, and the like) encrypted on a on-road apparatus side, and alsoincludes route information regarding a check barrier (check barriernumber, date and time at which the vehicle passed through the checkbarrier), if the vehicle passes through the mid-route (check barrier),which will be described later in detail.

A transmission circuit 50 which transmits as a response signal a datasignal including an ID code is connected to the signal processingcircuit 46. The transmission circuit 50 is connected to a transmissionantenna 52. The vehicle-mounted apparatus 30 transmits the data signalfrom the signal processing circuit 46 via the transmission antenna 52.The transmission antenna 52 may be provided to function as atransmission/reception antenna.

An IC card read/write device 60 is connected to the vehicle-mountedapparatus 30 so as to read data from the mounted IC card 62 and to writedata in the IC card 62. The IC card read/write device 60 is equippedwith a limit switch 58 which mechanically detects insertion of the ICcard 62. Whether the IC card is inserted may be optically detected bydetermining whether light is interrupted by the inserted IC card using aphoto-interrupter formed with a light emitting element and a lightreceiving element being disposed opposite to each other.

Connected to the signal processing circuit 46 are a display 54 comprisedof an LCD or a CRT for displaying whether the IC card is inserted ornon-inserted and other information including the card value balance, anda ten-key pad 56 (a simple push-button switch may also be used) whichinputs a signal to the signal processing circuit 46.

As shown in FIG. 4, the on-road apparatus for a vehicle traveling alongthe lane 202 is comprised of the mid-route antenna 218 and the mid-routeantenna control device 232. The mid-route antenna 218 is comprised of atransmission antenna 22 and a receiving antenna 26. The mid-routeantenna control device 232 is provided with a signal processing circuit12 structured so as to include a microcomputer. The microcomputer storestherein a processing program which will be described later. The signalprocessing circuit 12 can be connected to a central computer 400 (notshown).

The signal processing circuit 12 is connected to a transmission circuit14 which generates a data signal including an instruction. Thetransmission circuit 14 is connected to the transmission antenna 22 anda signal from the transmission circuit 14 is transmitted from thetransmission antenna 22. Further, connected to the signal processingcircuit 12 is a receiving circuit 24 to which the receiving antenna 26for receiving a signal transmitted from the vehicle-mounted apparatus 30is connected. The receiving circuit 24 fetches and outputs a data signalincluded in the signal transmitted from the vehicle-mounted apparatus30, via the receiving antenna 26.

Also connected to the signal processing circuit 12 is the memory 28. Thememory 28 in advance stores therein the electronic key A. Encryption oftransmitted information and decoding of received information areeffected using the electronic key A in the on-road apparatus at themid-route. The memory 28 also in advance stores therein the securitymechanism M used for transfer of data between the IC card 62 and thememory 28.

Other structures in the mid-route 200 are the same as theabove-described ones, and therefore, descriptions thereof will beomitted. Further, respective antennas and antenna control devices at theentrance gate and the exit gate are substantially the same in structureas those referred to above, and descriptions thereof will be omitted.

In the above-described vehicle-mounted apparatus and on-road apparatus,an antenna formed with a transmission antenna and a receiving antennabeing separated from each other is used. However, atransmission/reception type antenna may be used.

Further, in the above-described embodiment, the same electronic key isused both for encryption and decoding, but different electronic keys mayalso be used.

As shown in FIG. 5, the IC card 62, which can be inserted in thevehicle-mounted apparatus 30, is comprised of a microcomputer includinga CPU 64, a RAM 66, a ROM 68, the memory 70, and an input/output (I/O)port 72, which are connected by a bus 74 so as to allow transfer of acommand or data therebetween. The memory 70 is used to store thesecurity mechanism M and various information. The ROM 68 stores thereina processing routine which will be described later. The input/outputport 72 can be connected to the vehicle-mounted apparatus 30. Althoughnot illustrated, the IC card 62 is provided with a power source circuitso as to supply a power source when necessary.

The above-described IC card can store, as various information,information regarding the vehicle-mounted apparatus such as a cardnumber, balance information, information about utilization details(entrance gate number, exit gate number, toll, time and date ofutilization, and the like), and also can store a certified key code forhaving a card correspond to a vehicle-mounted apparatus.

Next, an operation of the present embodiment will be described.

A description will first be given of communication processing which ismutually effected between an on-road apparatus and the vehicle-mountedapparatus. FIG. 11 shows a main process effected in each of the on-roadapparatus, the vehicle-mounted apparatus, and the IC card, and a flow ofinformation which is mutually transferred therebetween.

As shown in FIG. 7, in step 114, the on-road apparatus located in themid-route transmits an inquiry signal until it receives a responsesignal from the vehicle-mounted apparatus 30. When the on-road apparatusreceives the response signal (when the decision of step 116 isaffirmative), in the subsequent step 118, gate information, in thiscase, route information is encrypted by the electronic key A(corresponding to process S1 shown in FIG. 11). In step 120, a signalincluding the encrypted route information and the like is transmitted(corresponding to a transfer w1 in FIG. 11). The above-described inquirysignal includes information that indicates the kind of gate at which theon-road apparatus is provided. The information that represents the kindof gate includes, for example, a gate number expressed by a commonsentence or simple common-sentence information such as “entrance”,“mid-route”, and the like.

Further, in the on-road apparatus at the entrance gate, substantiallythe same processing as the above-described one is effected, but in placeof the signal including the route information and the like, a signalincluding an entrance gate number indicating an entrance gate, and thelike is encrypted and transmitted. Further, in the on-road apparatus atthe exit gate as well, substantially the same processing as theabove-described one is effected. A toll receiving operation effected viacommunications will be described later.

The on-road apparatus as can transmit, to the vehicle-mounted apparatus,simple common-sentence information as the information that indicates thekind of gate. Other information may also be selectively indicated ascommon-sentence information or encryption information in the on-roadapparatus by separating from each other beforehand information that maybe made into a common sentence as simple common-sentence information,and information that should be encrypted as encryption information.

As described above, the on-road apparatus 10 transmits to thevehicle-mounted apparatus 30 the encryption information, and therefore,the information transferred between the on-road apparatus 10 and thevehicle-mounted apparatus 30 can maintain secrecy, and security withrespect to interception of information is improved.

FIG. 6 shows in detail communication processing of the vehicle-mountedapparatus. When in step 102 the vehicle-mounted apparatus waits until itreceives an inquiry signal from the on-road apparatus, and then receivesthe inquiry signal (when the decision of step 102 is affirmative), inthe subsequent step 104, the vehicle-mounted apparatus reads vehicleinformation (for example, an ID code such as an identification code thatspecifies a driver's own vehicle) and transmits, as a response signal, asignal including the vehicle information.

When in step 106 the vehicle-mounted apparatus waits until it receives asignal from the on-road apparatus and then receives the signal (when thedecision of step 106 is affirmative), it is determined thatcertification of the on-road apparatus and the vehicle-mounted apparatushas been completed, and in the subsequent step 108, it is determinedwhether accounting processing is required by determining whether thekind of gate indicates the exit gate using the information included inthe inquiry signal and indicating the kind of gate at which the on-roadapparatus is provided. When the kind of gate is the exit gate,accounting processing is required, and therefore, the decision of step108 is affirmative. In step 112, the accounting processing is executed,as will be described later, and the present routine ends.

On the other hand, when the kind of gate is an entrance gate or amid-route, the accounting processing is not required, and therefore, thedecision of step 108 is negative and the process proceeds to step 110.In step 110, information transmitted from a gate at which the accountingprocessing is not required, namely, encryption information based on thesignal received in step 106 is stored in the storage circuit 48 as is(corresponding to a process S6 in FIG. 11) and the present routine ends.Accordingly, the contents of the entrance information or routeinformation are stored in the storage circuit 48 of the vehicle-mountedapparatus 30 in a state of being left encrypted.

As described above, since the entrance information or route informationis maintained in the vehicle-mounted apparatus 30 in a state of beingleft encrypted, it becomes difficult to intercept the informationtransferred between the on-road apparatus 10 and the vehicle-mountedapparatus 30 resulting from a common-sentence structure and secrecy ismaintained, thereby resulting in improvement of security with respect tointerception of information. Further, the vehicle-mounted apparatus maymerely store the encrypted information and does not need to provide aprocessing portion for encryption or decoding. For this reason,irregularities in charge payment caused by alteration, reproduction, andfalsification due to disassembly inspection of a vehicle-mountedapparatus or analysis of a cipher are made impossible and the deviceconfiguration can be simplified.

Next, a description will be given of processing at an exit gate.

As shown in FIG. 9, when in step 136 an on-road apparatus installed atan exit gate transmits an inquiry signal including the kind of gateuntil it receives a response signal from the vehicle-mounted apparatus30 and the on-road apparatus then receives the response signal (when thedecision of step 138 is affirmative), in the subsequent step 138, theon-road apparatus transmits an information read-out requesting signal tothe vehicle-mounted apparatus 30. This step 138 gives a request forreading out the encryption information stored in the storage circuit 48of the vehicle-mounted apparatus 30 to the vehicle-mounted apparatus.Subsequently, when in step 140 the on-road apparatus transmits theinformation read-out requesting signal until it receives a signal fromthe vehicle-mounted apparatus 30 and the on-road apparatus then receivesthe signal (when the decision of step 142 is affirmative), in thesubsequent step 144, the electronic key A is read and the receivedsignal is decoded using the electronic key A (corresponding to a processS2 in FIG. 11).

Meanwhile, different electronic keys A can be used at the time ofencryption and decoding, and an electronic key B (≠A) used for decodingmay be stored and used.

In the subsequent step 146, using the decoded entrance information androute information and information regarding the type of a vehicle storedin the vehicle-mounted apparatus, tolls charged the vehicle in adistance from the entrance gate, the mid-route, and until the exit gateare calculated, and data or command is generated which is used tocollect automatically the calculated tolls using the IC card(corresponding to a process S3 in FIG. 11). In the subsequent step 148,the generated data or command is encrypted by the security mechanism Mof the IC card (corresponding to process S4 in FIG. 11), and in thesubsequent step 150, the encrypted data or command is transmitted. Thedata or command encrypted in step 148 is transmitted through thevehicle-mounted apparatus and is transferred to the IC card, as will bedescribed later in detail (corresponding to a transfer w3 in FIG. 11).

In the subsequent step 152, the on-road apparatus waits until itreceives a signal from the vehicle-mounted apparatus, and when theon-road apparatus receives the signal (when the decision of step 152 isaffirmative), in the subsequent step 154, the signal is decoded by thesecurity mechanism M of the IC card. The received signal is aninformation signal from the IC card. In other words, the encryptioninformation outputted from the IC card 62 is transmitted by thevehicle-mounted apparatus in a state of being left unchanged(corresponding to the transfer w3 in FIG. 11). Further, when the IC carddoes not have the security mechanism M, as will be described later, theIC card sends back to the on-road apparatus the encryption informationin a state of being left unchanged, for example.

In the subsequent step 154, the received signal is decoded. In step 156,based on a determination as to whether the data or command transmittedin the above-described step 150 has been sent back left unchanged, it isdetermined whether accounting processing has been carried out using theIC card 62 mounted on the vehicle-mounted apparatus 30. When thetransmitted data or command has been sent back left unchanged, thedecision of step 156 is affirmative, and in step 158, the data orcommand is encrypted by a security mechanism different from the securitymechanism M. Thereafter, the process returns to step 150 and theabove-described process is repeated.

In the foregoing, first, a cipher is transmitted by the securitymechanism M. When this mechanism is different from that at the side ofthe IC card 62, it is sequentially changed to the different mechanism,and thereafter, encryption is effected so as to allow coincidence ofsecurity mechanisms. Alternatively, first, the mechanism at the side ofthe IC card 62 is interrogated, and based on the answer thereto, thesecurity mechanism may be determined. As a result, even when onesecurity mechanism to be used is selected from a great number ofsecurity mechanisms, high speed processing becomes possible.

On the other hand, when the decision of step 156 is negative, it isdetermined that the accounting processing has been carried out using theIC card 62. In the subsequent step 160, it is determined whether thereceived signal includes data indicating that reception of tolls hasbeen completed. When the signal does not include such data, the decisionof step 160 is negative and the process returns to step 152. When thereceived signal includes the data which indicates that reception oftolls has been completed, the decision of step 160 is affirmative. Inthe subsequent step 162, utilization details regarding reception oftolls are prepared (corresponding to a process S5 in FIG. 11), and arefurther transmitted, together with an end signal, to the vehicle-mountedapparatus in the form of a common sentence without being encrypted(corresponding to a transfer w5 in FIG. 11). Meanwhile, the preparationof utilization details effected by the on-road apparatus and thetransmission of the end signal to the vehicle-mounted apparatus may alsobe carried out in the IC card 62 (corresponding to a transfer w6 in FIG.11).

FIG. 8 shows in detail, as processing effected by the vehicle-mountedapparatus, an exit gate process in step 112 shown in FIG. 6. In step122, the vehicle-mounted apparatus waits until it receives theinformation read-out requesting signal transmitted from the on-roadapparatus. When the vehicle-mounted apparatus receives the informationread-out requesting signal (when the decision of step 122 isaffirmative), in the subsequent step 124, the encryption informationstored in the storage circuit 48 is read out as is left unchanged. Inthe subsequent step 126, the encryption information is transmitted as isleft unchanged (corresponding to a transfer w2 in FIG. 11).

In the subsequent step 128, the vehicle-mounted apparatus waits until itreceives a signal from the on-road apparatus, and when thevehicle-mounted apparatus receives the signal (when the decision of step128 is affirmative), in the subsequent step 130, the on-road apparatus10 and the IC card 62 are bypassed. Namely, the received signal from theon-road apparatus 10 is outputted to the IC card 62 in a state of beingleft unchanged, and the output signal outputted from the IC card 62 istransmitted to the on-road apparartus 10 in a state of being leftunchanged (corresponding to the passing through the vehicle-mountedapparatus indicated by the transfer w3 and w4 in FIG. 11). This receivedsignal and output signal are encrypted, and therefore, they may betemporarily stored in the vehicle-mounted apparatus.

In the subsequent step 132, it is determined whether the received signalincludes an end signal in the form of a common sentence. When the signaldoes not include the end signal, the decision of step 132 is negativeand the process returns to step 128. When the signal includes the endsignal, the decision of step 132 is affirmative, and in step 134,bypassing of the on-road apparatus 10 and the IC card 62 is cancelled,and in the subsequent step 135, the received utilization details forreception of tolls is indicated (corresponding to a process S7 in FIG.11).

FIG. 10 shows a process of the IC card 62; it is determined whether asignal is inputted from the vehicle-mounted apparatus 30. When a signalis not inputted, the decision of step 164 is negative and the decisionof step 164 is made repeatedly. On the other hand, when a signal isinputted (corresponding to the transfer w4 in FIG. 11), the decision ofstep 164 is affirmative. In the subsequent step 166, a signal inputtedby decoding processing included in the security mechanism M is decoded(corresponding to a process S8 in FIG. 11). In the subsequent step 168,it is determined whether the decoded signal is a read/write requestgiven to the IC card 62.

When the inputted signal cannot be decoded or when a request other thanthe read/write request is given, the decision of step 168 is negative.In the subsequent step 170, a signal inputted from the vehicle-mountedapparatus is sent back in a state of being left unchanged, andthereafter, the process returns to step 164. As a result, correspondenceof an IC based on a plurality of different security mechanisms is madepossible. On the other hand, when the process for the IC card 62 is therequest for reading and writing date, the decision of step 168 isaffirmative. In the subsequent step 172, it is determined whether therequest is that for writing, and when the request is that for writingdata, the decision of step 172 is affirmative, and the process proceedsto step 174. When the request is that for reading, the decision of step172 is negative and the process proceeds to step 180.

In step 174, data is written in the memory 70 by the security mechanismM. For example, reception of tolls in which tolls that are decoded datafrom the on-road apparatus is charged with respect to the balance ofcharges for accounting and the resulting balance of charges (balanceinformation) is written in the memory 70 (corresponding to a process S9in FIG. 11). In the subsequent step 176, the data written in the memory70, for example, the balance information and a toll-reception completionsignal are encrypted by the securing mechanism M and are, in step 178,outputted to the vehicle-mounted apparatus 30 (corresponding to thepassing through the vehicle-mounted apparatus and outputting to theon-road apparatus indicated by the transfer w4 in FIG. 11).

In step 180, data is read from the memory 70 by the security mechanismM. In the subsequent step 182, the read data balance information, forexample, is encrypted, and in step 178, it is outputted to thevehicle-mounted apparatus 30.

As described above, in the present embodiment, among information to becommunicated between the on-road apparatus and the vehicle-mountedapparatus, information such as entrance information or routeinformation, which has a high secrecy to prohibit alteration thereof, isused in a state of being left encrypted (in the form of encryptioninformation) and the encrypted information is temporarily stored in thevehicle-mounted apparatus as it is. Accordingly, alteration ofinformation such as entrance information or route information becomesdifficult; therefore, the reliability of the information itself can beimproved and the secrecy thereof can be maintained.

Further, in a case in which reading and writing is effected for an ICcard in which user information regarding a user such as the balance ofcharges or the like is stored, when information is transferred using theencryption information encrypted by the security mechanism of the ICcard itself and the information of the IC card is outputted via thevehicle-mounted apparatus which transmits and receives information toand from the on-road apparatus, or when the information from the on-roadapparatus is inputted, the vehicle-mounted apparatus merely allowspassing of the encrypted information and does not decode theinformation. Accordingly, information is not altered and the secrecythereof can be maintained.

Moreover, the vehicle-mounted apparatus merely allows passing of theencryption information therethrough, and therefore, the vehicle-mountedapparatus does not need to provide processing for encryption ordecoding. As a result, the structure of the vehicle-mounted apparatus issimplified and a calculation load of the vehicle-mounted apparatus canbe reduced.

Further, in the road-to-vehicle communications, a two-way communication(optical communication or the like is also possible) is employed and thepresent invention can be applied thereto.

The above-described system can be applied to a road or a parking areafor simple reception of tolls wherein a gate is not present.

Further, in the above-described system, there was described a case inwhich a vehicle-mounted apparatus includes neither a structure nor aprocess for encryption and decoding, but a common sentence-structuredportion may be deleted by well-known general encryption.

Second Embodiment

Next, a second embodiment will be described. Further, this embodimenthas substantially the same structure as that of the above-describedembodiment, and therefore, the same members as those of theabove-described embodiment will be denoted by the same referencenumerals and detailed descriptions thereof will be omitted.

As shown in FIG. 12, an automatic toll receiving system of the presentembodiment is structured to include the on-road apparatus 10 provided onthe road side and the vehicle-mounted apparatus 30 mounted on a vehicle.Information is mutually transferred between the on-road apparatus 10 andthe vehicle-mounted apparatus 30 by radio communications. An on-roadapparatus communicating with the vehicle-mounted apparatus 30 includesantennas for transmitting and receiving various information and isdisposed in each of an entrance gate of a toll road, a mid-routethereof, and an exit gate. The on-road apparatus 10 includes a memory 28(see FIG. 14) in which the electronic key A is stored, and thevehicle-mounted apparatus 30 includes the storage circuit 48 (see FIG.13) in which electronic keys A, B, and C are stored, as will bedescribed in detail later. When information is mutually transferredbetween the on-road apparatus 10 and the vehicle-mounted apparatus 30 byradio communications, transmitted information is encrypted and receivedinformation is decoded, using the electronic key A.

The above-described encryption and decoding can be provided using asecret key encryption system (for example, Data Encryption Standard(DES)).

The IC card 62 (described in detail later) in which various informationis stored is detachable from the vehicle-mounted apparatus 30.Information is mutually transferred between the vehicle-mountedapparatus 30 and the IC card 62. The IC card 62 includes the memory 70(see FIG. 15) in which the electronic key B is stored. When informationis transferred between the vehicle-mounted apparatus 30 and the IC card62, transmitted information is encrypted using the electronic key B andreceived information is decoded.

The type of a vehicle on which the vehicle-mounted apparatus 30 ismounted or vehicle information such as an ID number may be written inthe vehicle-mounted apparatus 30. The vehicle information is writtenusing an information writing device 76. The information writing device76 includes a memory 84 in which the electronic key C is stored (seeFIG. 15). When the vehicle information is transferred between thevehicle-mounted apparatus 30 and the information writing device 76, thevehicle information is encrypted using the electronic key C and receivedinformation is decoded.

Next, the vehicle-mounted apparatus 30 and the on-road apparatus 10communicating with the vehicle-mounted apparatus 30 will be described indetail. The present embodiment will be described with an on-roadapparatus provided in the mid-route 200 being given as an example.Further, for simplifying explanation, the mid-route antenna 218 providedfor radio communication with the vehicle 90 traveling along the lane 202and the mid-route antenna control device 232 are used. A vehicle-mountedbattery (not shown) is connected to the vehicle-mounted apparatus 30.

Similar to the above-described embodiment, in the mid-route 200 of thepresent embodiment, the two lanes 202 and 204 are provided side by side.The arch 216 on which the route recognizing antennas 218, 220, and 222are disposed is provided between the ground 208 and the ground 214 insuch a manner as to extend over the lanes 202 and 204. (see FIG. 2).

As shown in FIG. 13, the vehicle-mounted apparatus 30 includes thereceiving antenna 32 for receiving a data signal transmitted from theon-road apparatus. The receiving antenna 32 demodulates a receivedmodulated wave and is connected to a demodulation circuit 34 forobtaining the data signal. The demodulation circuit 34 can also obtain acarrier wave of an electric wave transmitted from the on-road apparatusand may be connected to the transmission circuit 50. The demodulationcircuit 34 is connected via the data signal receiving circuit 44 to thesignal processing circuit 46 including a microcomputer. Themicrocomputer of the signal processing circuit 46 stores therein aprocessing program and the like, as will be described later.

The storage circuit 48 is connected to the signal processing circuit 46.The storage circuit 48 in advance stores therein the electronic keys A,B, and C. Further, the information writing device 76 can be connected tothe signal processing circuit 46 and information regarding avehicle-mounted apparatus is stored in the storage circuit 48. Namely,when the vehicle-mounted apparatus is mounted on a vehicle, a vehiclenumber (the number recorded on a number plate) serving as an ID code isstored in the storage circuit 48 by the information writing device 76and information regarding the type of the vehicle on which thevehicle-mounted apparatus is mounted is also stored in the storagecircuit 48. Further, when the IC card 62 is inserted, information aboutthe balance (such as information about the money left and the result ofupdating of the balance at the time that the IC card 62 is used within aservice area at which the vehicle stops midway) of the IC card 62 isstored in the storage circuit 48. Further, when the vehicle has passedthrough an entrance gate, a vehicle-type code detected at the entrancegate and entrance information (entrance number, date and time of passageof the vehicle, and the like) are stored in the storage circuit 48. Whenthe vehicle has passed through a mid-route (check barrier), checkbarrier information (check barrier number and date and time of passageof the vehicle) corresponding to the passed check barrier is stored inthe storage circuit 48. And when a communication error arises,communication error information (type of error, positions at which theerror occurred (type of gate, gate number, antenna number, and thelike), date and time of occurrence of the error, the number of timesthat an error occurs, and the like) or the like is stored in the storagecircuit 48.

The transmission circuit 50 for transmitting, as a response signal, adata signal including an ID code, and the like is connected to thesignal processing circuit 46. The transmission circuit 50 is connectedto a transmission antenna 52. The vehicle-mounted apparatus 30 modulatesa carrier wave obtained by demodulating the modulated wave received atthe receiving antenna 32, based on a data signal from the signalprocessing circuit 46 and can send back the modulated carrier wavethrough the transmission antenna 52. Meanwhile, the transmission antenna52 is provided so as to function as a transmitting/receiving antenna. Anunmodulated carrier wave transmitted from the on-road apparatus isreceived by the transmission antenna 52, and thereafter, the unmodulatedcarrier wave may be modulated by the transmission circuit 50 based onthe data signal from the signal processing circuit 46, so as to be sentback via the transmission antenna 52.

Further, the IC card read/write device 60 for reading data from the ICcard 62 inserted therein and writing data into the IC card 62 isconnected to the vehicle-mounted apparatus 30. The limit switch 58 formechanically detecting the insertion of the IC card 62 is provided inthe IC card read/write device 60. Whether the IC card has been insertedinto the IC card read/write device 60 may be optically detected bydetermining, using a photo-interrupter composed of a light-emittingelement and a light-receiving element disposed opposite each other,whether light is cut off by the inserted IC card.

The display 54 comprised of an LCD or CRT for displaying whether the ICcard has been inserted, the balance, and the like thereon, and the tenkey 56 for inputting a signal to the signal processing circuit 46 areeach connected to the signal processing circuit 46.

As shown in FIG. 14, the on-road apparatus for a vehicle traveling alongthe lane 202 is comprised of the mid-route antenna 218 and the mid-routeantenna control device 232. The mid-route antenna 218 is comprised ofthe transmission antenna 22 and the receiving antenna 26. The mid-routeantenna control device 232 has the signal processing circuit 12including a microcomputer. The microcomputer stores therein a processingprogram which will be described later. The signal processing circuit 12can be connected to a central computer 400 (not shown). The signalprocessing circuit 12 is connected to the transmission circuit 14 whichgenerates a data signal including an instruction (a communicationrequesting signal). The transmission circuit 14 is connected via a mixer18 to the transmission antenna 22. A carrier wave generation circuit 20which generates a carrier wave having a predetermined frequency isconnected to the mixer 18. The mixer 18 mixes a signal inputted from thetransmission circuit 14 and a carrier wave inputted from the carrierwave generation circuit 20 and modulates the carrier wave inputted fromthe carrier wave generation circuit 20 with the signal inputted from thetransmission circuit 14. Further, the modulated wave is transmitted as aradio wave from the transmission antenna 22.

Connected to the carrier wave generation circuit 20 is the receivingcircuit 24 which fetches a data signal from the modulated wave modulatedand sent back from the vehicle-mounted apparatus 30 and received by thereceiving antenna 26. The receiving circuit 24 is connected to thesignal processing circuit 12. Further, the receiving circuit 24 isconnected to the carrier wave generation circuit 20 and a carrier wavetransmitted for comparison of the carrier wave included in the signalsent back from the vehicle-mounted apparatus 30 is inputted thereto.

Other structures in the mid-route 200 are the same as theabove-described ones, and therefore, descriptions thereof will beomitted. Further, respective antennas and antenna control devices at anentrance gate 100 and an exit gate 300 are substantially the same instructure as those referred to the above, and therefore, descriptionsthereof will be omitted.

Further, in the above-described vehicle-mounted apparatus and on-roadapparatus, an antenna comprised of the transmitting and receivingantennas separated from each other is used. However, atransmission/reception type antenna may be used.

As shown in FIG. 15, the IC card 62 which can be inserted in thevehicle-mounted apparatus 30 is comprised of a microcomputer includingthe CPU 64, the RAM 66, the ROM 68, the memory 70, and the input/output(I/O) port 72, which are connected by the bus 74 so as to allow transferof a command or data therebetween. The memory 70 is used for storage ofthe electronic key B and various information. Further, the ROM 68 storestherein a processing routine which will be described later. Theinput/output port 72 can be connected to the vehicle-mounted apparatus30 or to the IC read/write device 60. Further, although not illustrated,the IC card 62 is provided with a power source circuit so as to supply apower source constantly.

The above-described IC card can store, as various information,information regarding the vehicle-mounted apparatus such as a cardnumber, balance information, information about utilization details(entrance gate number, exit gate number, toll, date and time ofutilization, and the like), and also can store a certified key code forhaving a card correspond to the vehicle-mounted apparatus, namely,recording the electronic key B.

Further, there can be used, as the IC card, various cards, for example,a memory card such as an LSI card, a magnetic card, a hologram card onwhich information can be optically recorded and reproduced, or amagneto-optical card on which information can be magneto-opticallyrecorded and reproduced.

The information writing device 76 for writing the information regardingthe vehicle-mounted apparatus in the above-described vehicle-mountedapparatus 30 can be connected to the vehicle-mounted apparatus 30 and iscomprised of a microcomputer including a CPU 78, a RAM 80, a ROM 82, amemory 84, and an input/output (I/O) port 86, which are connected by abus 88 so as to allow transfer of a command or data. The memory 84 isused for storage of the electronic key C and various information. TheROM 82 stores therein a processing routine, which will be describedlater. The input/output port 86 can be connected to the vehicle-mountedapparatus 30.

Next, an operation of the present embodiment will be described.

First, a process for writing vehicle information in the vehicle-mountedapparatus 30 will be described.

FIG. 16 shows a process routine in the information writing device 76 forwriting vehicle information in the vehicle-mounted apparatus 30. Whenthe process is executed, in step 200, vehicle information such as thetype of vehicle on which the vehicle-mounted apparatus 30 is mounted, anID number, and the like, which is to be written in the vehicle-mountedapparatus 30, is set. In the subsequent step 202, the electronic key Cis read and the set vehicle information is encrypted by the electronickey C. In the subsequent step 204, the encrypted vehicle information isoutputted to the vehicle-mounted apparatus 30 (see an output C1 in FIG.21). The information writing device 76 thus encrypts the vehicleinformation to be outputted and maintains the secrecy of theinformation.

FIG. 17 shows a process routine of the vehicle-mounted apparatus whenthe vehicle information is written therein. In step 206, thevehicle-mounted apparatus waits until information is inputted thereto,and when information is inputted, in step 208, the electronic key C isread and the inputted information is decoded by the electronic key C. Inthe subsequent step 210, it is determined whether the decodedinformation is the vehicle information. When the decoded information isnot the vehicle information, it is determined that other processing iseffected or false information is given (when the decision of step 210 isnegative), and the present routine ends. On the other hand, when thedecoded information is the vehicle information (when the decision ofstep 210 is affirmative), in step 212, the decoded vehicle informationis written in the storage circuit 48. As described above, in thevehicle-mounted apparatus 30, the encrypted information is decoded andit is determined whether the decoded information is the vehicleinformation. Accordingly, there is no possibility of the inputtedinformation being incorrectly written in the vehicle-mounted apparatus.

Next, intercommunication processing between the on-road apparatus andthe vehicle-mounted apparatus will be described.

FIG. 18 shows in detail communication processing of the vehicle-mountedapparatus. In step 214, the vehicle-mounted apparatus waits until itreceives a signal from the on-road apparatus (see a transfer A1 in FIG.23). When the vehicle-mounted apparatus receives the signal (when thedecision of step 214 is affirmative), in the subsequent step 216, theelectronic key A is read and the received signal is decoded by theelectronic key A. In the subsequent step 218, it is determined whetherthe decoded signal is an inquiry signal. When the decoded signal is notan inquiry signal, the decision of step 218 is negative, and the processreturns to step 214. When the decoded signal is an inquiry signal, thedecision of the step 218 is affirmative and the process proceeds to step220.

In step 220, the electronic key A and the vehicle information (forexample, an ID code such as an identification code which specifies avehicle), and the vehicle information is encrypted by the electronic keyA. In the subsequent step 222, with the received inquiry signal beingused as a carrier wave, a modulated wave wherein the carrier wave ismodulated with the encrypted vehicle information is transmitted as aninquiry signal (a transfer A2 in FIG. 23).

Next, in step 224, the vehicle-mounted apparatus waits until it receivesa signal from the on-road apparatus (a transfer A3 in FIG. 23). When thevehicle-mounted apparatus receives the signal (when the decision of step224 is affirmative), in step 226, the received signal is decoded by theelectronic key A. In the subsequent step 228, by determining whether thedecoded signal includes entrance information, it is determined whetherthe vehicle is presently passing the entrance gate. When the vehicle isnot passing the entrance gate (when the decision of step 228 isnegative), the process proceeds to step 230. When the vehicle is passingthe entrance gate, in step 232, entrance gate processing (the transferA4 to An in FIG. 23) is executed. In this entrance gate processing, instep 506, the entrance information which is an entrance gate numberincluded in the received signal is stored in the storage circuit 48 ofthe vehicle-mounted apparatus 30.

In step 230, based on a determination as to whether the decoded signalincludes a mid-route code (check barrier information), it is determinedwhether the vehicle has passed the mid-route 200. When the vehicle haspassed the mid-route 200 (when the decision of step 230 is affirmative),in step 234, mid-route processing is executed. When the vehicle has notpassed the mid-route 200 (when the decision of step 230 is negative), itis determined that the vehicle has passed an exit gate, and in step 236,exit gate processing is executed.

In this mid-route processing, mid-route information based on a mid-routecode included in the decoded signal is stored in the storage circuit 48of the vehicle-mounted apparatus 30. Further, in the exit gateprocessing of step 514, based on information regarding the type ofvehicle stored in the vehicle-mounted apparatus, balance informationstored in the IC card mounted in the vehicle-mounted apparatus, and atoll table recorded in advance in the vehicle-mounted apparatus, tollscharged on a route from the entrance gate to the exit gate with themid-route located therebetween are calculated from the present balance,and the charged tolls are automatically collected. After the tolls havebeen normally collected, entrance information is cleared. In themid-route processing or in the exit entrance processing, transfer ofinformation indicated by the transfer A4 to An shown in FIG. 23 iscarried out in accordance with the number of processes. The transfer ofinformation to the IC card will be described later.

As shown in FIG. 19, in step 238, an on-road apparatus located in amid-route reads the electronic key A and encrypts an inquiry signal bythe electronic key A. In the subsequent step 240, the on-road apparatustransmits the encrypted inquiry signal (see the transfer A1 in FIG. 23).

Subsequently, the on-road apparatus transmits the encrypted inquirysignal until it receives the response signal from the vehicle-mountedapparatus 30, and in the subsequent step 242, it is determined whetherthe on-road apparatus has received the signal from the vehicle-mountedapparatus 30. When the on-road apparatus has received the signal, thedecision of step 242 is affirmative, and in the subsequent step 244, thesignal is decoded using the electronic key A. When the on-road apparatushas not received the signal (when the decision of step 242 is negative),the process returns to step 238.

In the subsequent step 246, it is determined whether the decoded signalis a response signal. When it is the response signal (when the decisionof step 246 is affirmative), in step 248, gate information, in thiscase, mid-route information is encrypted using the electronic key A. Inthe subsequent step 250, the on-road apparatus transmits a signalincluding the encrypted mid-route information and the like (see thetransfer A3 in FIG. 23).

Meanwhile, in the on-road apparatus at the entrance gate, substantiallythe same process as the above-described one is executed, but the on-roadapparatus transmits, in place of the signal including the mid-routeinformation and the like, a signal including an entrance gate number,which represents the entrance gate, and the like. Further, in theon-road apparatus at the exit gate 300 as well, substantially the sameprocess as the above-described one is executed, but the toll receivingprocessing may be executed by a signal including an exit coderepresenting an exit gate, and the like or by radio communications.

In the transfer of a signal between the above-described on-roadapparatus 10 and the vehicle-mounted apparatus 30, information isdecoded by the electronic key A. Accordingly, the informationtransferred between the on-road apparatus 10 and the vehicle-mountedapparatus 30 maintains secrecy, and the security to the interception ofinformation can be improved.

Next, a process for the transfer of information between the IC card 62and the vehicle-mounted apparatus 30 will be described. In thefollowing, processing in the IC card read/write device 60 connected tothe vehicle-mounted apparatus 30 will be described, and the presentinvention can also be applied to a case in which an IC card read/writedevice is independently located at a recovery gate or the like.

FIG. 20 shows a process in the IC card 62. In step 252, it is determinedwhether a signal is inputted from the vehicle-mounted apparatus 30. Whena signal is not inputted, the decision of step 252 is negative and thedecision of step 252 is made repeatedly. On the other hand, when asignal is inputted (see a transfer B1 in FIG. 22 and the transfer B1 inFIG. 23), the decision of step 252 is affirmative, and in step 254, theIC card reads the electronic key B and decodes the inputted signal bythe electronic key B. In the subsequent step 256, it is determinedwhether the decoded signal is a read/write request given to the IC card62. When the inputted signal is a request other than the read/writerequest, the decision of step 256 is negative, and the process returnsto step 252. On the other hand, when the process effected for the ICcard 62 is the request for reading and writing, the decision of step 256is affirmative. In the subsequent step 258, it is determined whether therequest is that for writing. When the request is that for writing data,the decision of step 258 is affirmative, and the process proceeds tostep 260, and when the request is that for reading data, the decision ofstep 258 is negative, and the process proceeds to step 266.

In step 260, a request for output of data is given to thevehicle-mounted apparatus 30 (see a transfer B2 in FIG. 22 and atransfer B2 in FIG. 23), and the data is inputted to the IC card. Theinputted data is decoded in step 262 and the decoded data is written inthe memory 70 in step 264.

In step 266, the data stored in the memory 70 is read, and in thesubsequent step 268, the data is encrypted by the electronic key B. Instep 270, the data is outputted to the vehicle-mounted apparatus 30 (seethe transfer B2 in FIG. 22 and the transfer B2 in FIG. 23).

Accordingly, the information transferred between the vehicle-mountedapparatus and the IC card is allowed to maintain secrecy so as toimprove the security with respect to the interception of theinformation.

As described above, in the present embodiment, at the time ofcommunication of information between the on-road apparatus and thevehicle-mounted apparatus and in the transfer of information between thevehicle-mounted apparatus and the IC card or between the vehicle-mountedapparatus and the information writing device, the information isencrypted or decoded using different electronic keys. For this reason,even when the secrecy of one electronic key leaks out, disclosure of thesecrecy of a system can be kept to a minimum. Accordingly, thereliability of data held by each system can be improved and the load ofeach system can be reduced by the secrecy which is based on a smallnumber of electronic keys.

Meanwhile, the above-described system can be applied to a toll road of asimple toll collecting system, or a parking area, wherein a gate is notpresent. For this reason, this system can be used only for reception oftolls or transfer of simple information such as parking time, time forpassage, and the like, and the system of the present embodiment caneasily be applied.

The above-described process routine may be executed using a floppy disk(FD) serving as a recording medium without being stored in a memory orROM of each of the on-road apparatus and the vehicle-mounted apparatus.In this case, in the on-road apparatus, a floppy disk unit (FDU) inwhich a floppy disk can be removably inserted may be connected to aninput/output port of the signal processing circuit 12 or the like, andin the vehicle-mounted apparatus, a floppy disk unit (FDU) in which afloppy disk can be removably inserted may be connected to aninput/output port of the signal processing circuit 46 or the like. As aresult, the above-described process routine or the like can be read outand written in a floppy disk using the FDU, and a program can berecorded in advance in the floppy disk without being stored in a ROM orthe like, and the processing program recorded in the floppy disk via theFDU can be executed. Further, in place of the FDU, a mass storage (notshown) such as a hard disk device is connected to the input/output portand the processing program recorded in the floppy disk may be executedby being stored (installed) in the mass storage (not shown). Further, asthe recording medium, an optical disk such as a CD-ROM, or aphoto-magnetic disk such as an MD, MO, or the like is provided. Whenthese disks are used, a CD-ROM device, an MD device, an MO device, orthe like may be used in place of or in addition to the above-describedFDU.

INDUSTRIAL APPLICABILITY

As described above, the vehicle-mounted communication device androad-to-vehicle communication device according to the present inventionare suitably used for the vehicle-mounted communication device mountedon a vehicle and for the road-to-vehicle communication device in whichcommunication processing is effected between the vehicle-mountedcommunication device and an on-road apparatus located on the road side,and are, for example, applied to an automatic toll receiving system forautomatically receiving a toll for a vehicle running on a toll road orthe like or a vehicle parked in a toll parking area.

1. A vehicle-mounted communication device comprising:transmitting/receiving means provided for wireless communication ofinformation with road-side communication means located at a road side;relay means that relays encryption information, received from the roadside by said transmitting/receiving means, to an IC card and that relaysoutput information encrypted by the IC card to thetransmitting/receiving means, in an undecoded state, the IC cardincludes a) storage means that stores user information regarding a userfor charge-processing, b) encryption means that encrypts the outputinformation which is based on the user information and outputs theencrypted output information, and that decodes encrypted inputinformation relating to the user information, and c) output means thattransmits a portion of the output information in a state without beingencrypted; information display means that displays information; andencryption information storage means in which the encryption informationis temporarily stored, wherein the transmitting/receiving means storesthe encryption information in the encryption information storage meansand transmits the encryption information stored in the encryptioninformation storage means as it is, and the information display meansreceives and displays the portion of the output information, which isoutput from the output means in the state without being encrypted.
 2. Aroad-to-vehicle communication device comprising: a vehicle-mountedcommunication device according to claim 1; and road-side control meansbeing located at a road side, including road-side communication meansprovided for intercommunication of information with the vehicle-mountedcommunication device, and also including road-side encryption means forencrypting transmitted information and decoding received information. 3.A road-to-vehicle communication device according to claim 2, whereinroad-side encryption means of said road-side control means installed atan entrance gate effects encryption of transmitted information androad-side encryption means of said road-side control means installed ata toll reception gate effects only decoding of received information. 4.A road-to-vehicle communication device according to claim 2, wherein thetransmitted information is accounting information regarding accountingprocessing of charged facilities.
 5. A road-to-vehicle communicationdevice according to claim 3, wherein the transmitted information isaccounting information regarding accounting processing of chargedfacilities.
 6. A vehicle-mounted communication device according to claim1, wherein the encryption information is temporarily stored in thevehicle-mounted communication device in an undecoded state.
 7. Avehicle-mounted communication device according to claim 1, wherein theroad-side communication means further transmits non-encryptedinformation, and the information display means receives and displays thenon-encrypted information.